The legal complaint by a U.S.-based Islamic lobby group asking a federal judge to expunge all copies of a best-selling exposé that documents the group’s terrorist ties is an attempt to eliminate evidence that could lead to criminal prosecution, according to a lawyer defending a co-author of the book.

Daniel Horowitz, who represents “Muslim Mafia” co-author P. David Gaubatz and his son, Chris, believes the Council on American-Islamic Relations, or CAIR, knows that the material is incriminating and wants it destroyed.

“So far, the Obama administration has refused to prosecute CAIR,” Horowitz said, “despite undeniable evidence that following 9/11 they sought donations for 9/11 victims and passed the money to the Hamas-based Holy Land Foundation.”

CAIR has insisted its designation by federal prosecutors as an unindicted co-conspirator in the Justice Department’s terror-finance case against the Richardson, Texas-based Holy Land Foundation is unjustified. But the group admitted in a legal brief in 2009 that it solicited donations in the wake of the 9/11 attacks for Holy Land Foundation, which was convicted of funneling more than $12 million to Hamas.

In May 2007, CAIR was named an unindicted co-conspirator in the scheme.